Serbia’s Novak Djokovic moved a step closer to defending his Italian Open title after dominating Japan’s Kei Nishikori 6-3, 3-6, 6-1 in a one-sided semi-final in Rome on Friday.

Djokovic, who beat Rafael Nadal in last year’s final to claim his third trophy in the Italian capital, will now meet David Ferrer in the semis on Saturday when he will be highly fancied to account for the Spaniard.

In their 19 meetings so far, Djokovic has won 14 times. Although Ferrer has won three of their five meetings on clay, his last victory against the Serbian on the surface was during a Davis Cup match in 2009.

Djokovic has won their past two meetings on clay, including a three-set quarter-final in Rome last year.

But, admitting he has yet to reach the form that saw him beat Tomas Berdych in the final of the Monte Carlo Masters last month, Djokovic warned an upset could be on the cards.

“I have to be honest and say I haven’t been playing as well in this tournament as I did at Monte Carlo. The level I want to get on is still not there,” said Djokovic.

“But little by little it’s coming together.

“Hopefully I will be able to play better — more consistent, less unforced errors, less ups and downs in tomorrow’s match — because I have another clay court specialist, one of the best competitors on the Tour, somebody that is not going to hand me the win.

“He (Ferrer) is going to make me work.”

Djokovic had warned after a hard-fought third round win over Brazilian Thomaz Bellucci on Thursday that his Japanese opponent would be a tough customer.

But after levelling the match at one set apiece, the hard-hitting Nishikori’s challenge fizzled out in a third set that saw the fifth seed grow increasingly frustrated at his inability to match Djokovic’s clinical and varied game.

Djokovic swung the match in his favour when he broke Nishikori in the fourth game of the third set, stretching his advantage to 4-1 with a forehand volley at the net in the next game.

“That break in the third set was crucial,” added the Serbian. “I knew that breaking his serve would give me wings.

“I started swinging through the ball better and made less unforced errors and the match was gone in a very short time.”

Nishikori said: “After the second set I thought I was playing well. In the third set he was just very solid. He wasn’t missing any easy balls and even with the tough conditions he was very steady.

“After he broke me in the third he started playing much better, so it was tough to stop him.”

A Djokovic victory over Ferrer on Saturday could set up a final clash with Roger Federer or Rafael Nadal on Sunday.

Earlier, Federer — bidding for his maiden Rome title having suffered three final defeats including two to Nadal — remained on course for a semi-final clash with the Spaniard after cruising past Tomas Berdych 6-3-, 6-3 in just over an hour.

He will meet Nadal in the last four if the Spaniard overcomes Swiss Stan Wawrinka in their semi-final scheduled for 1900 GMT on Friday.

But Federer admitted beating Spain’s seven-time champion would be a “huge challenge”.

“Everyone who has played against Nadal knows he’s the best mover on clay, on both sides of the court. He’s perfected it,” said Federer.

“It’s always a huge challenge when you play him on clay.”

Russia’s Maria Sharapova, the last winner of the women’s title in the past five years still in contention in Rome, faces Victoria Azarenka of Belarus later in a bid to secure her place in the last four against Daria Gavrilova, who beat fellow-qualifier Christina McHale 6-2, 6-4.